Impact-tool.



C. EKBERG.

IMPACT TOOL.

APPLICATION FILED FEB. 3. 1915.

Patented Mar. 14, 1916.

2 S'HEETS-SHEET 1.

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IMPACT TOOL.

APPLICATION FILED FEB. 3. 1915.

Patented Mar. 14, 1916.

2 SHEETS-SHEET 2.

' INVENTOR Carl Ekberg BY WITNESSES NJ. MEI/M THE COLUMBIA PLMflouRAPn c0., WASHINGTON. D. C.

can; EKBERG, or nvnnnrr, wns rrnoro i.

M A -root- Patented Mar. 14., 19155.

Application filed February 3,1915. Serial No. 5,893.

To all whom it may concern:

Be it known that I, CARL EKBERG, a citi- Zen of the United States, and a resident of Evereth'in the county of Snohomislrand State of Washington, have invented a new and Improved ImpactaTool, of which the following is a full, clear, and exact description.

This invention relates to improvements in impact tools wherein a reciprocating piston is operated by fluid pressure, such'as compressed air, and in which the piston serves the purpose of a hammer to strike successive and numerous blows against the tool shank for cutting, calking or riveting in metal or stone Work and various other purposes. g

A further object of the invention is to provide an improved impact tool or air hammer by which the elimination of complicated valve structures is accomplished for all sizes of tools, varying from the stone masons engraving hammer, which is very light, up to' the ordinary chipping and calking hammer, as well as riveting hammers, and the invention is characterized by the use of a throttle to control the supply of motive finichsnch as compressed air, steam or analogous elastic fluid pressure, to the casing of the tool for the actuation of a hammer piston therein, the casing and piston being provided with a novel arrangement of ducts or ports and passages whereby the hammer is under direct pressure on its forward and return strokes and exhaust fromieither end is arranged to provide a cushion at the limit of each stroke whereby shocks and jars incident to a device of this character are reduced to a minimum, inoperation'of the device obviated and the manual manipulation of the tool by the operator greatly facilitated.

With the above and other objects in view, the invention resides in the peculiar combination and arrangement of parts to be hereinafter more fully described, illustrated and claimed, it being also an object to provide a device which is simple in construction, durable and efiicient in operation and not likely to get out of working order.

Reference is to be had to the accompanying drawings forming a part of this specification, in which similar characters of reference indicate corresponding parts in all the views and in whichT Figur.e 1 is a side elevation ,of an impact tool or airhammer constituting my inve-nticn; Fig. 9 is-a longitudinal sectional view thereof with the piston of the hammer in a position prior to its movement on a forward or operativestroke; Fig. 3 is a similar view thereof with the piston in a position prior to its return stroke; Fig. 4 is a cross sectional view taken on the line 44 of Fig. 3; Fig. 5 is a cross sectional view taken on the line 5,5 of Fig. 3; Fig. 6 is a longitudinal sectional view of the casing of the hammer at right angles to Fig. 2'; Fig. 7 is a detail elevation of the piston.

In the drawings, the numeral 10 designates the handle of the impact tool or hammer which may be of any preferred design but which is shown shaped in the manner of the handle of a pistol or revolver and adapted to fit the curvature of the hand when grasped for manually operating the device. This handle is of angular or curved form and is designed to be grasped by one or both hands of the operator as distinguished from the use of the ordinary saw style of handle commonly employed in this type of tool. Furthermore, the handle is provided with a longitudinal feed passage 11 which is adapted to be placed in communication with a flexible or other feed pipe or tube 12 having threaded connection therewith, as shown at 13, whereby the tool can be attached or detached at will. The other end of the handle is in the nature of a socket is the lateral wall of which is interiorly threaded while the passage 11' communicates with said socket.

In order to control the supply of motive fluid, preferably compressed air, from the passage 11 to said socket a throttle or valve 15 isprovided, the same being of circular cross section and snugly movable in a transverse opening 16 of corresponding cross section in the enlarged or sleeve portion of the handle producing the socket 14. T he opening 16 is drilled or otherwise formed from one side of the handle and terminates short of the other side at a diametrically opposite point where a restricted opening 17 is provided in such a manner that the valve may be fitted in the opening 16 and the stem portion 18 thereof caused to extend through the reduced opening 17 after which an operating button '19 is mounted on said stem to permit actuation of the'valve or throttle by repression or depression of the same in the opening 116. This opening is;

then closed by a plug which may be threaded thereinto, and the valve, which is of relatively cylindrical form, has an annular groove 21 in its peripheral surface and an end recess 22 forming a seat for an expansible coiled spring 23 which is disposed between the plug and the end wall of said recess so as to hold the valve toward the end wall of the opening 16 through which the reduced opening 17 is provided thus hold the valve or throttle, and

more particularly the operating head or button thereof, projected from the handle.

. The valve is of less. length than the length of the opening 16 so as to be adapted for movement therein andwhen held in the position mentioned by the spring 23 the passage '11 will be closed so asto cut off com-' munication through the same but permit said communication to be made upon the thrcttle or valve being repressed against the action of the spring to aline the groo-ve'21 with said passage, as shoWn in Fig. 3 ofthe drawings. The plug 20 is provided with an opening 24 through whichsuch motive fluid or air. as may have escaped between the throttle and the'plugQO may pass out to the atmosphere in order to prevent the formation of an air pocket and requiring ternal annularrib 29 and an outer flange on said. nose piece. The casing is provided with a longitudinal bore producinga chamber 30 for accommodating a piston 31 which serves as 'a hammering medium, and the shank portion 26 of the tool extends partly intothe chamber 30. The other end of the casing is closed by a cylindrical disk 32' which is fitted in the sleeve portion of'the socket and clampedtight against the end of the casing when the latteris secured in the socket, the disk 32 having a stepped face 33 which provides a space at the adjacent end of the casing. The disk 32 which consti-, tutes a closure forthe bore of the. casing at r the handle end thereof is secured to the easing by a locking pin 32 which holds the disk against rotation while the 5 clamping thereof as described and shown holds the same in air tight connection with the casing.

The piston is of cvlindricalform but is provided with an axial longitudinal chamber or passa e 34 which terminates short of the ends of the piston; and which'is preferably made bydrilling through the rear end ofthe latter and closing said bore by a plug 35. The piston is further provided'with a pair of longitudinally spaced annular chan- 7 nels 36 and 37 respectively, which are placed in communication with the chamber 34 near the ends of the latter through the instrumentality of a series of radial ducts-38 and j 39 respectively. Leading longitudinally through the wall of the casing at one side and communicating with the socket space are a pair of feed passages 40 having 'in-' let ports 1-1 communicating with the piston chamber 30 nearer tov the rear end of said chamber than the forward end thereof, while communication is established centrally with said chamber through the medium of auxiliary inlets 4-2. Diametrically opposite,

or in ether suitable relation tothe passages 40, the casing is provided with longitudinally extending ports or ducts 4'3 and 44 re-' spectively, the same being spaced apart centrally of the casing and the former leading to opposite ends of the piston chamber and having lateral end portions connecting the same with said chamber. The duct 43 .h 15

communication with the piston chamber ad-' ditionally through an auXiliar-yinlet 45 near the end of saidductremote from the handle.

In the operation of the device as described, and with the parts in the position shown in Fig.2'of the drawings, the throttle valve 15 normally prevents the admission ofalr or other m'otivefluid to the interior of the casing for reciprocating the piston therein, but upon .the throttle valve. being depressed air will be admitted to the feed passages 40 and will escape through the ports or ducts 41, channel 37 "and ducts 39 into the passage or chamber 3% and then through the ducts 39 and channel 36, through the lateral portions of the ducts 43 to move the piston forwardly to the position shown in Fig. '3 of the drawings. -Under the diioo rect pressure and assisted by its momentum V the piston, acting as a hammer,'will be carried beyond the last named position to strike the shank of the tool and impart an operative blow to the latter, but as the piston assumes the position shown in Fig. 3air will escape into the opposite end of the chamber in the casing through the channel 36, passage 34 and channel 37. by the ducts connecting the same, and then through the passages .44 through themedium of thelateral extensionsof the latter. In this manner this pistonwill be acting against direct pressure prior to or after the delivery of theblow or impact so that the action"thereoffwill be.

materially cushioned to avoid jars' and shocks being transmittedto the operator,

and in'addition to ouicken the return of the piston and form eflicient means for timing 7 the stroke of'the latter and the speed of 'recipr cation thereof.

. Whenthepiston has traveled forwardly:

a distance equal to'the length of the recessed air space in the piston the air is cut ofi', the channels 36 and 37 at this time straddling the inner lateral ducts or extensions of the passages ell, as shown in dotted lines in Fig. 2 of the drawings, and as the piston is returned under the action of direct pressure by the escape of the air foryva'rdly thereof and the parts are in the position shown in Fig. 3 of the drawings, the exhaust takes place through the diametrically opposite exi'iaus't ports 46 and through longitudinal exhaust passages 47 communicating with the forward end or nose of the casing so as to discharge the exhaust air away from the operator. The stroke is then continued as heretofore described, the exhaust on the forward stroke taking place through exhaust ports 48 communicating with the passages 47 near the rear ends of the latter, the passages a7 extending longitudinally throughout the greater portion of the length of the casing, as is more particularly shown in Fig. 6 of the drawings.

In order to prevent the piston or piston hammer from stopping on the dead center or remaining in a position where neither one of the channels 36 or 37 is placed in communication with the feed passage 40, if the piston should ever happen to stop where the air will be shut off, that is, in a central position as shown in dottedlines in Fig. 3 of the drawings, the feed passage l0 will be placed in communication with either of the passages 43 or 44: through the instrumentality of the auxiliary inlet ports or ducts 42 and 45, and in this manner air will be admitted for moving the piston toward the port which acts as a supply port, depending upon the direction of the stroke or movement of the piston. On the return stroke of the piston the parts will be in the position as shown in Fig. 2, so that air will be admitted in rear of the piston to act as a cushion and otherwise as heretofore described in connection with the forward movement or stroke of the piston.

In practice all ofthe parts are preferably made of tool steel except the handle whicn. will be made of mild steel, while the piston, the throttle and the nose piece or plug will be of hardened steel, the handle being of any convenient or desired shape. The sizes of the devices may vary according to the work required but by way of explanation it may be said that in an impact tool or hammer in which the piston weighs about two and one half ounces 3500 or more blows per minute will be struck, and the hammer can be operated to strike a verv light blow as the balance obtained is easily regulated by regulating the force of the air through the medium of the throttle.

Having thus :describedmyinvention, what.

I claim as new and desire to secure by Let ters Patent is 1. An impact tool, comprising a tool holding casing having sliding connection with the tool employed and provided with a piston hammer chamber, a reciprocating piston hammer mounted in the chamber and having an intermediate axial passage with ducts branching therefrom and external annular channels adapted to be placed under fluid pressure, an inlet port to be placed successively in communication with said channels, exhaust ports which are opened and. closed by the piston hammer and longitudinally extending ducts leading from points inspaced relation adjacent to the central part of the chamber to the ends thereof and placed in successive communication with different annular channels so as to be alternately supplied with fluid pressure for action against the piston hammer to reciprocate the latter.

2. An impact tool, comprising a tool holding casing having sliding connection with the tool employed and provided with a piston hammer chamber, a reciprocating piston hammer mounted in the chamber and having an intermediate axial passage with ducts branching therefrom and external annular channels adapted to be placed under fluid pressure, an inlet port to be placed successively in communication with said chan nels, exhaust ports which are opened and closed by the piston hammer, longitudinally extending ducts leading from points in spaced relation adjacent to-the central part of the chamber to the ends thereof and. placed in successive communication with different annular channels so as to be alternately supplied with fluid pressure for action against the piston hammer to reciprocate the latter and serving at intervals to admit fluid pressure at the non-pressure end of the piston hammer to cushion the latter at the limits of its strokes toward and away from the tool after the actuation of the piston hammer by direct pressure and means for controlling the supply of fluid pressure to the inlet port.

3. An impact tool of the class described, comprising a casing having a longitudinal bore producing a chamber, the nose of the casing having a sliding connection with the tool employed, said casing having an inlet passage designed to be placed in communication with the fluid pressure supply and having communication with the chamber to one side of the longitudinal center thereof, spaced passages in the casing for communication with the chamber of the latter at points spaced apart and, at either side of the point of communication of the inlet passage therewith and at the ends of said chamber, a piston mounted to reciprocate inthe chamber and. having a pairof spaced. v1

channels placed in communication with each other at all times through the piston, said piston when in one position serving to admit fluid pressure to one end of the chamber for forcing the piston in the opposite direction and for similarly supplying fluid pressure to the other end of the chamber when in the last named position by causing said channels to be successively and alternately placed in communication with the inlet pass sage and the last named passages communicating with the chamber at either side of the feed passage and atthe ends of said chamher to reverse the positionrofthe piston after the latter has struck the tool and exhaust passages communicating with the chamber for exhausting the fluid pressure at the end of each stroke, said passages having longitudinal portions communicating with the nose end of the casing.

4. An impact tool of the class described, comprising a casing having a longitudinal bore producing a chamber, a tool having sliding connection with the nose of the casing and limited in its displacement therein, said casing having an inlet passage designed to be placed in communication with the fluid pressure supply and having communication with the chamber to one side'of the longitudinal center thereof, spaced passages in the casing for communication with the chamber of the latter at points spaced apart and at either side of the point of communication of the inlet passage therewith and at the ends of saidchamber, a piston mounted to reciprocate in the chamber and having a pair of spaced channels placed in communication. with each other at all times through the piston, said piston when in one position serving to admit fluid pressure to one end of the chamber for forcing the pisten in theopposite direction and for simi larly supplying fluid pressure toflthe other end of the chamber when in the last named position by causing said channels to be successively and alternately placed in communication with the inlet passage and the last named passages communicating with the chamber at either side of the feed passage and at the ends of said chamber to reverse the position of the piston after the latter has struck the tool, exhaust passages communi cating with the chamber for exhausting the fluid pressure at the end of each stroke, a disk closing the bore of the casing at one end and limiting the movement of the piston toward said end with a space therebetween, means for controlling the supply of fluid pressure to the feed passage of the casing, and auxiliary inlet ducts establishing communication with the feed passage and with either of the passages leading to the chamher at the end of the casing, the said auxiliary ducts being placed in communicationwith said channels of the piston when 7 stroke. a

5. An air hammer, comprising a casing having a c1rcular longitudinal bore, a tool,

having sliding connectionwith the casing at one end, a closure for the other end of the casing, said casing having an inlet port for the fluid pressure supply and having longitudinal inlet passages communicating with the inlet port and having communication with the chamber produced by said bore near the center thereof, said casing at an apposite point being provided with longitus dinal passages spaced'apart at their inner ends and'communicating with the ends of said chamber and with exhaust ports communicating with the tool end of the casing, a cylindrical piston mounted to reciprocate in the chamber to form a hammer, said cas: ing having auxiliary ports establishing com: munication between the inlet passages and the last named passages leading to the end of the casing having the; closure, beyond the points of communication thereof with the chamber, said piston having a longitudinal passage termlnating short of the ends thereof, spaced annular grooves and a plurality of radial ducts connecting the passage and grooves, said grooves being alternately placed in communication with the inlet passages and the inlet ends of the other passages, alternately supplying compressed air to the ends of the chamber for reciprocating the piston and serving at each stroke to ad-..

mit direct air pressure counter to the moving force in a predetermined relative degree to the impact of the piston with the tool, whereby the operation of the piston may be regulated, theexhaust taking place near the limit of each stroke. a 7

6. Animpact tool, comprising a tool holdin casin havinma lon itudinal bore form- C) b b D ing a chamber, a too-l having sliding connection with the casing, a reciprocating piston hammer mounted in said chamber and having an axial passage closed at each and and ducts branching from said passage, the piston hammer having external annular channels spaced apart and communicating at all times with each other through the said ducts and the axial passage of the piston hammer, the said casing having an inlet port and a longitudinally extending inlet passage communicating with the inlet port and havingcommunication with the chamber of the casing to one side of the longitudinal center thereof, the said casing also having chamber, the said last mentioned passages leading to the ends of the casing chamber, the said annular channels being adapted to be placed successively in communication With the said inlet passage, and the said last mentioned passages being placed in successive communication with different annular channels to be alternately supplied With fluid pressure for action against the piston hammer to reciprocate'the same, the said casing having auxiliary ducts for establishing communication through the piston hammer between the inlet passage and one of said last mentioned passages When the piston hammer is in a dead center position, and means for controlling the supply of fluid pressure to the inlet port, said casing having exhaust ports opened and closed by the piston hammer.

7. An impact tool, comprising a tool holding casing having a longitudinal bore forming a chamber, a reciprocating piston hammer mounted in said chamber and having an axial passage closed at each end, the piston hammer having external annular channels spaced apart and communicating with each other through the piston hammer, the

said casing having an inlet passage for the fluid supply having communication With the chamber of the casing, the said casing also having passages for communicating with the casing chamber at points at either side of the point of communication of the inlet passage with said chamber, the said last mentioned passages leading to the ends of the casing chamber, the said annular channels being adapted to be placed successively in communication With the said inlet passage, and the passages leading to the ends of the casing chamber being placed in successive communication with different annular channels to be alternately supplied with fluid pressure to reciprocate the piston hammer, said casing having exhaust ports controlled by the piston hammer.

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses.

JOHN STELLING. PETER HANSEN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

